1. Field of the Invention
The present invention generally relates to a compressor used in a refrigerating system and, in particular, it relates to a reciprocating type compressor having single headed pistons.
2. Description of the Related Art
In the type of compressors used in refrigerating systems for compressing a cooling gas, a muffling effect can be expected from reducing a pulsation in the pressure of a suction gas or a discharge gas. For example, a swash plate type compressor including a pulsation reduction device is disclosed in Japanese Unexamined Utility Model Publication (Kokai) No. 50-44313 and U.S. Pat. No. 5,051,069. In these prior art references, the compressor includes double headed pistons and front and rear discharge chambers arranged on the front and rear sides of the double-headed pistons. A discharge passage axially extends between the front and rear discharge chambers, and is arranged in a region of the cylinder block between the adjacent cylinder bores. This arrangement is only possible for a compressor having double headed pistons since a circumferential distance between the adjacent cylinder bores is relatively large. The pulsation reduction device can thus be relatively easily arranged near the axially central region of the compressor so that the pulsation reduction device is in fluid communication with the axially extending discharge passage.
In the case of a swash plate type or wobble plate type compressor having single headed pistons, it is usual to arrange a suction inlet and a discharge outlet in the cylinder head (rear housing), because the compression chambers are arranged on only one side of the pistons. It is necessary to increase the number of the cylinder bores compared with that of the compressor having double headed pistons in order to secure a desired discharge capacity, resulting in a region between the adjacent cylinder bores that is too narrow to provide a discharge passage between the adjacent cylinder bores. Therefore, in most prior art devices having single headed pistons, a pulsation reducing device for absorbing a pulsation in the discharge pressure is incorporated in the cylinder head. Also, there is a proposal, as shown in FIG. 10, in which a discharge muffling chamber "c" is arranged in a cylinder block "a" in communication with a discharge chamber "b", and a suction muffling chamber "f" is arranged in a cylinder head "d" in communication with a suction chamber "e".
However, the provision of the pulsation reducing device in the cylinder head results in an enlarged size of the cylinder head. In particular, in the case of a compressor equipped in an automobile, there is a severe demand for parts having lighter weight and a smaller size, and an extension of the length of the compressor is very disadvantageous. In addition, it has been recognized that the positioning of the suction and discharge ports which are connected to the refrigerating circuit is restricted to the rear of the compressor, leading to an inconvenient piping arrangement when the compressor is mounted to the automobile. In addition, in the arrangement of FIG. 10, it is necessary to provide caps k.sub.1 and k.sub.2 and seals S.sub.1 and S.sub.2 on the muffling chamber "c" and "f", respectively, resulting in an increased cost.